Then it was all true. I saw the skins of tigers flaming in his palace on the Grand Canal; I saw him opening a chest of rubies to ease, with their crimson-lighted depths, the gnawings of his broken heart.

Because of the medal and picture, Carraway believes in all the amazing things Gatsby claimed to have done. Even though Gatsby seems suspicious, the evidence seems convincing enough. Carraway thinks about Gatsby’s grand world adventures.

The “Grand Canal” could be a reference to the famous canal in Venice Italy. It could also be the Beijing-Hangzhou Grand Canal in China. The Canal in China is the longest artificial river in the world.